WASHINGTON » President Barack Obama announced today he would appoint longtime foreign policy adviser and popular West Wing staffer Denis McDonough to lead his staff.

Obama, appearing with McDonough at the White House, called him indispensable and "a great friend to me and everybody who works here at the White House."

McDonough is taking over the chief of staff job from Jack Lew, Obama’s nominee for Treasury secretary.

Obama said McDonough has played a key role in every one of the major national security decisions of his presidency, including the end of the war in Iraq, winding down the war in Afghanistan, responses to natural disasters in Haiti and Japan and repeal of the military’s ban on openly gay service members.

McDonough’s place in Obama’s inner circle was illustrated during the Navy SEAL raid that killed Osama bin Laden in May 2011. He is among those whose images are captured in a White House photograph seated in the situation room with Obama and other senior officials watching the raid unfold.

Obama complimented McDonough for being so humble, visiting troops serving in Iraq and Afghanistan and wounded warriors at Walter Reed National Military Medical Center without fanfare or cameras to learn about the needs of the troops. "Then he comes back here to the White House, and he gets it done. That’s the kind of focus and the kind of heart I want here in the White House," Obama said.

He said McDonough also is tough, having been raised in Minnesota as one of 11 children. And he teased the former St. John’s University football player as making up for modest talents with determination and a high tolerance for pain.

Earlier, McDonough worked as a foreign policy specialist in Congress, including as a senior foreign policy adviser to former Senate Majority Leader Tom Daschle, D-S.D., before moving to Obama’s Senate office.

McDonough’s new role was previously filled by Rahm Emanuel, William Daly and Pete Rouse, as interim chief of staff, before Lew.

Other senior personnel shifts were made today, including the appointment of Obama chief congressional lobbyist Rob Nabors as McDonough’s deputy for policy. Vice President Joe Biden’s national security adviser, Tony Blinken, is taking over McDonough’s post as deputy national security advisor.

Katy Kale is being promoted from to assistant to the president for management and administration after serving as the deputy for that post. Assistant Attorney General Lisa Monaco, head of the Justice Department’s National Security Division, was selected to take over for John Brennan as advisor for homeland security and counterterrorism once his nomination as head of the Central Intelligence Agency is confirmed.

White House communications director Dan Pfeiffer is being promoted to senior advisor. Pfeiffer deputy Jennifer Palmieri will take over as communications director.

Miguel Rodriguez is being named to take over the top lobbying post after serving under Nabors, and Obama campaign staffer David Simas is being named a deputy senior advisor for communications and strategy.

The White House announced today that Chris Lu, an aide who has been with Obama since his time as a senator and most recently managed relations with his Cabinet, was leaving his post. The job will be taken over by Danielle Gray, formerly deputy director of the National Economic Council. In a statement, Obama praised Lu for overseeing "one of the most stable and effective Cabinets in history" and said he’s asked him to consider taking on another administration job after he takes some time off.